The present invention relates to an apparatus for lifting, lowering and/or handling an object, preferably an elongated cylindrical object such as pipe that is being lifted from or lowered into a well.
Heretofore, numerous devices and techniques have been utilized for the removal or installation of, water pipe, for example, as might be utilized in conjunction with a submersible pump in a well shaft. Quite frequently, a number of sections of pipe are involved such that the overall weight of the pipe chain, particularly when the lifting operation has just begun or the lowering operation is almost complete, becomes very significant. In fact, equipment for the removal or installation of such pipe chains, due to the extreme weight involved, and the fact that moisture and/or materials of construction of the pipe may present slippery surfaces, must be able to firmly grip the pipe surface and must also possess strength characteristics adequate to lift the overall pipe length and the pump. Quite bulky apparatus has thus heretofore been utilized for such purpose.
In similar fashion, in the drilling of oil wells, natural gas wells and the like, wherein lengths of pipe are secured to adjacent lengths and lowered in to the well, the same or similar problems exist. Again, numerous prior art attempts have been made to arrive at a successful means for raising or lowering such lengths of pipe. In both environs, as noted above, as well as others, not only is the surface of the pipe and the overall weight of the pipe chain important, further problems are generally encountered by virtue of the small size of the openings along which the pipe chain must move. A well for potable water, for example, may be 6 inches in diameter with a 1 inch pipe received therein. Such restrictive dimensions, of course, not only dictate a small size for the lifting apparatus but also for manipulation of same to ensure proper grip and/or release of the apparatus with respect to the pipe. When considered in light of the attendant strength requirements, the potential problems could be of major proportion.
The present invention represents a simple and efficient apparatus that is useful in deployment within restrictive dimensional situations for handling of water pipe, oil pipe, or the like within a well and is quite effective in providing a gripping action along the exterior pipe surfaces which will fail only due to structural failure of components of the apparatus. In fact, the apparatus of the present invention functions somewhat analogously to a Chinese handcuff toy in that the stronger the pull, the greater the gripping power. Quite oppositely, however, effective release of gripping power may be easily inplemented.
Known prior art for apparatus for engaging and lifting objects include U.S. Pat. Nos. 4,097,084 to Russell; 3,295,883 to G. Dupuy et al; 1,797,482 to F. E. Prockish; 882,796 to L. T. Pedigo; 1,457,445 to H. Marcum; 853,234 to J. G. Rountree; 2,697,001 to H. R. McGraw; 3,360,292 to D. M. Trammel; and 910,062 J. A. Holmberg. None of the above listed patents are believed to be anticipatory or suggestive of the apparatus of the present invention.